Recorder



June 4 1946 G. KEINATH rs1-AL 2,401,356

RECORDER Filed April 17, 1944 3 Sheets-Sheet l Y .lNvEN'roRs Geary@ He/na/y and MM l Jun 4, 1946. G. KEINATH ET'AL 2,401,356

RECORDER Filed April 17, 1944 5 Sheets-Sheet 3 Patented .Jute 4, 19462' lcarrito STATES PATENTl OFFICE RECORDER George Keinath, Larchmont, N. Y., and Reinhard K. Hellmann, Meriden, Conn.; said Heumann assigner to Connecticut Telephone and Electric Division, Great American Industries, Incorporated, Meriden, Conn., a corporation of Deia- Waffe Application April 17, 1944, Serial No. 531,375

Our invention is related to that of the cepending application of Reinhard K. Hellmann'for Recording apparatus, Serial No. 531,374, filed April 17, 1944, and concerns recording apparatus for measuring, facsimile transmitting, and the like purposes.

In recording apparatus of the type here referred to, a stylus and a recording surface are movable relative to each other in two coordinate .directions so that th'e stylus is capable of producing a record on the surface during such relative travel. For instance, in known drum type recorders, a cylinder or drum member which accommodates a recording sheet on its peripheral surfacerevolves about its geometrical axis while the stylus translates in parallel to this axis. Drum rotation and stylus translation are reprewith two measuring or control quantities, one of which is frequently time. In other lmown recorders, the diagram or. record is plotted on an advancing, non-rotating recording strip by means of a, stylus travelling transverse to the motion of the strip (stripchart recorders). Drum type recorders, generally, permit a, higher operating speed, but render it difiicult or virtually impossiblevto observe the record while it is being. produced by the stylus. Stripchart recorders, as a f rule, avoid this dilculty but are not as readily applicable for high recording speeds and lead to more complicated designs as compared with' drum type recorders.

vIt is an object of our invention to provide recording apparatus which not only permit an observation of the record or diagram while it is being recorded but which render it also possible to displace the nascent record relative to the stationary structure of the apparatus without ren quiring an interruption of the recording pera` tion.

Referring to recorders with a manually sta*-V ionary recording drum and a stylus rotating about the drum and translating axially thereof,

it is one of the more specific objects of our in.

vention to aord turning th'e drum about its axis into any convenient position during a recording operation without delaying or otherwise impairing the progress of the recording operation.

In order to achieve these objects,` and in accordance with our invention, we provide a recording apparatus with a stylus and a sheet supporting or otherwise accommodating member that are movable relative top e'ach other in two coordinate directions while the sheet support is 12 Claims. (Cl. 23d-1.5)

further capable of superposed motion in parallel to one of the two coordinate directions in order to permit displacing the record sheet. The, apparatus is further equipped with a control device, such as a-variable electric impedance or potentiometer device, a mechanical potentiometric or y tensiometric device or a start-stop device or resentative of the two coordinates of the diagram to be recorded and are controlled in accordance Vso lease mechanism, in which the position or motion of two relative movable members is a controlling factor of th'e recording operation. For instance,

when the recording apparatus contains an electrical or mechanical potentiometric or tensiometric device, the relative position of its two control members 'at which a comparative (standard) voltage or tension is .balanced by the effect of the magnitude to be recorded, determines the point on the recording sheet Where the stylus produces a recording mark. In a start-stop facsimile recorder, to mention another example, the relative position of th'e stop and release members of the start-stop control device determines lthe starting the' connection between the record producing devices and the control device is formed by mechanical transmission or gear means disposed on a common base structure with stylus, sheet support and'control device.

According to a more specific feature of the invention, the sheet support is connected by a transmission with one of the two relatively movable members of the control device so as to move simultaneously with and proportionately to'anyl sh'eet displacement in the above-'mentioned direction, and the stylus is similarly connected by transmission means with the other member of the control device. Consequently, when the stylus moves, the connected control member movesalso and in a given transmission ratio to the corresponding component stylus motion; and when the sheet is moved along a corresponding path, the other control member is moved in a given ratio tothe sheet displacement' thereby increasing or reducing therelativ'e travel between the two control members depending upon the direction of the sheet displacement.

These and other objects, advantages and features of our invention will be apparent from the following description of the examples illustrated in the drawings.

Figure 1 of the drawings is a part-sectional elevation of a recording apparatus according to our invention in which an electric resistance potentiometer is provided for controlling the writing operation of the stylus, the plane of section being indicated in Fig. 2 by L-I.

Fig. 2 is a sectional top view of the same recorder, the section being taken along a cut denoted in Fig. l by IIII.

Fig. 3 shows a part-sectional bottom view of the recorder of Figs. 1 and 2.

Fig. 4 relates to the same apparatus and rep resents a schematic and explainato1m diagram of some of its parts in. conjunction wi n example of electric circuit means suitable for operation; and

Fig. 5 is a diagrammatic .showing of another recorder according to the invention. applicable for facsimile recording and provided with a startstop device.

Referring to the recording apparatus illustrated in Figs. 1 through 4, the letter B denotes e. base structure which comprises s, housing II with a closure plate I2 and forms a base plate i3. 'A flange and sleeve member I4 is journalled in a base of base plate I3 and traversed by a shaft I5 to which it is keyed or fastened so as toirevolve together therewith. One end of shaft I5 engages a bore or bearing of the closure plate I2. An insulating disc I6 is firmly screwed to the flange portion .of member I4 and serves as an abutment for the insulating bottom plate I1 of a recording drum D for accommodating a recording sheet on its peripheral drum surface. Plate II has two marginal recesses I8 and I8 at opposite sides of its periphery (Figs. l and 2). Two leaf springs I9 and I9, fastened to the disc I6 extend through the recesses i8 and I8' respectively` and engage corresponding openings in the cylindrical Wall of the drum D. A knob 20 is rmly attached to drum D by means of a stud 2l which traverses an insulating bearing plate 22. An end plate 23 forming part of the rigid base structure B has an opening large enough to permit a. free passage of the drum D and is provided with dowel pins, such as the one denoted by 24 (Fig. 1), which engage corresponding bores of the bearing plate in order to hold it in centered position relative to the base structure.

'I'he drum with bottom plate I1 and beari plate 22 can be removed, for the purpose of attaching or exchanging a recording sheet, by pulling the knob 20 out oi' its seat with sufficient force to overcome the holding bias of the leaf springs Il and I9'. When inserting the drum assembly, the ends oi' the leaf springs snap into the corresponding openings of the drum wall and thus secure the drum in a. fixed relation to the shaft I3. The knob 20 also permits revolving the drum D into any convenient angular position, thereby causing the shaft I5 to participate in the revolution.

The stylus assembly S of the recorder comprises an electrode pin 2B attached to an angular holder 23 which is pivoted at 21 to a bracket 23. This bracket is firmly mounted on a flange portion 2l of an annular carrier member M which carries a gear 30. The flange portion 29 is en- UscedbythreeequsllylpacedrollersIlJlmd.

33 (see Fig. 2) revolvably mounted on an annular support 34. The two annular parts M and 34 surround the drum D coaxially but, while the member M with the stylus assembly is rotatable about the drum, the support 34 is prevented from rotary motion by engagement with two threaded shafts or feed screws 35 and 35 (Figs. l, 2 and 3) serving to advance the support 34 along the drum, thereby also moving member M and stylus assembly S in parallel motion along the peripheral drum surface. The engagement between the support 34 and each feed screw is obtained by two releasablenut devices (Figs. l and 2). Each device has a sleeve 31 or 31 in sliding engagement with the feed screw 35 or 35'. Each device has further a lever 33, pivoted at 39 to a ring shaped cover member 4i), which has a threaded nut portion 4I (41') extending through a slot oi sleeve 31 (31') and is biased by a spring 42 (42') toward engagement of nut portion 4i (43') withieed screw 35 (35'). In this manner, the support 34 is normally in operative engagement with the feed screws. A projection 43 (425V) of each lever extends toward an inwardly bent tongue 44 (44') formed by a cut-out portieri oi member 4i) but is normally out oi engagement therewith (Figs. l and 2). Member til is rotatable to a limited extent relative to support 34 and, if rotated by hand in the proper direction, will cause itsJ tongues 44 and 44' to e'ngage the respective cam surfaces of projections 43 and 43 and thus force the levers toward the drum axis against the bias of springs 42 and 42' thereby releasing the nut portions 4I and 4I from the feed shaft. The whole assembly carried by support 34 can then be slid up and down along the drum.

The stylus pin 25 is normally held against the surface of drum D by means of a spring 45. It is desirable to lift the stylus pin when manually displacing the assembly. To this end, a pin 46 extends loosely through the bracket 2B and car rier M so that its lower end lies closely above the skirt surface of cover member 4I). Member 4|! and support 34 are in threaded or cam engagement with each other at 41 (Fig. 1) so that, when the cover member 40 is rotated in order to release the carrier from the feed screws 35 and 35', the cover member is also moved toward support 34 and hence is forced against the pin 4G. As a result, holder 25 rotates counterciockwise about pivot 21 and lifts stylus 25 from the drum.

A shaft 49 extends through the base plate I3 (Figs. 2 and 3) toward and through the end plate 23 (Fig. 1) and is square or keyed along the length of drum D. Shaft 49 passes through a gear SII (Fig. 2) with a correspondingly noncircular opening, so that the gear cannot rotate but is free to slide relatively to shaft 43. Gear III has two bearings in the annular support Il and in a strip 5I, respectively, the strip being at- 4 accommodate the gear.

` axially along the drum by revolving the feed screws I5 and 26.

The transmission and drive means for actuatlng t,he shaft and screws are arranged within the housing I I o! base structure B as is apparent from Figs. 1 and 3. These means, as exemplied in the embodiment here described, refer to a record.

. er for diagrams in which the coordinate parallel to the drum axis represent time or is proportional to time. Shaft 49 for rotating the stylus assembly carries at its end a bevel gear 12 meshing with a bevel gear 53 on the shaft 54 of an electric motor 55 which is mounted on base structure- B. When the motor runs at constant speed, the

ystylus assembly is rotated about drum D at a sequently, the two feed screws will revolve at a fixed speed relative to that of the stylus rotation 4 and move the stylus slowly along the drum, for

instance, from the top to the bottom oi' the drum, the resultant stylus motion being along a helical path of many turns so as to scan the entire area of the recording surface during each complete recording period. At the end of its downward travel, the carrier may actuate a limit switch (not shown) which stops the drive or disengages the carrier from the feed screws. I

During the just-mentioned scanning motion, the stylus 25 runs idle, that is, it produces no Gear 51.

recording marks on the sheet placed on the drum D except at one or several points of each individual stylus rotation at which an electric current is passed between 'stylus and drum through the electroresponsive recording paper mounted on the drum. The electric means for controlling this marking 'operation comprise a variable cir-4 cuit member, oreferablyan impedance or potentiometric device, which has a movable adjusting or control member actuated in a fixed speed relation 'to one component of the stylus motion rela@ tive to the drum. in the embodiment of Figs. i to 3, the electric device for controlling the stylus operation consists of a resistance potentiometer P (Fig. 1) which has an insulating base 60 rmly mounted on shaft I5. The base 6U carries and encloses a resistor 68 (in Fig. 4) and is provided with a circular series of contacts, such as the one denoted by 6i (Fig. l), which are electrically connected to corresponding tap points of the resistor. An insulating hub 62, firmly mounted on bushing 48 carries a slide contact 66 for engaging the contacts 6I. A slip ring connection is provided for connecting the slide contact 62 through a brush arm 63 with a terminal 64 firmly secured to the potentiometer base 60. Two further terminals, such as terminal 65, serve to connect the potentiometer resistor into the appertaining measuring circuit, for instance, a circuit of the type described in a later place with reference to Fig. 4.

It follows from the foregoing that the base (and enclosed resistor) of potentiometer P is stationary as long as the drum D remains stationary and rotates together with the drum, whenever at ground potential.

the knob 20 is turned in order to change the angular position of the record sheet. It will also be understood that, since the slide contact 66 (Fig. 1) is geared to the shaft 49 through bushing 48 and gears 51 58 and 56 (Fig. 2), it will rotate simultaneously with the stylus assembly S and in a fixed ratio thereto. In the illustrated embodiment, the ratio of gears 5B and 51 is 1:1 while that of gears 50 to 30 is 1:3. Hence the slider 66 performs three full rotations for each complete rotation of the stylus;` That is, this particular apparatus is intended to operate as a multiple recorder which produces three records in three peripherally successive areas of the recording sheet as described in the copending application of George Keinath, Serial No. 470,088, filed D..- cernber 24.-, 1942, for Multiple recorder. The necessary movable contact for connecting three measuring gauges sequentially to the recorder may be mounted'on shaft 4t so as to operate in synchronism with the stylus rotation, but since these contact means do not form part of our invention proper and need not further be referred to for explaining the invention, they are not illus trated in the drawings.l if a single diagram area is to extend around the drum periphery, the ratio of gear transmission 61 t0 5d is so chosen that it is the same as that of gears all and 56.

In order to more fully explain the operation of a recording apparatus as described in the foregoing, the diagram oiFig. a will now bereferred to. The illustration shows some of the parts of the recorder structure in a schematic manner and in conjunction with one of the many electric circuits available for its operation. The reference characters applied in Fig. i to structure of the recording apparatus are identical with those used in Figs. l to 3 for designating corresponding parts, while those numerals in mg. a that differ from the corresponding ones of Figs. l to 3 only by a prime sign, `denote elements which have however, that the gear ratios according to Fig.' a' are so chosen as to effect a 1:11 transmission be= tween stylus rotation and slider rotation for the above-mentioned purposeoi single-diagram rea cording. The feed screws and other transmission and drive means for moving the stylus assembly v S axially along the drum D are not shown in Fig'. a because it will be clear from the foregoing that this translating motion is derived from gear 51 and that the annular member M, while rotated by gear 5i] through shaft 49 driven by motor 55, advances simultaneously in the axial direction of drum D, i. e. perpendicularly to the plane of illustration of Fig. 4. During each rotation of the stylus, the slider 66 of potentiometer P passes once through its complete cycle relative to the appertaining resistor 68.

The drum D has its shaft I5 connected with the base 60 of the potentiometer P. While this connection is direct in the embodiment of Figs. 1 to 3 it is represented in Fig. 4 as a gear transmission X and Y merely for the purpose of conlution of 'base 60 as in the showing of Figs. 1 to 3.

The drive and transmission mechanisms are The insulated drum D is connected to a control circuit C through a terminal lug 69 (Fig. 1). 'Ihe stylus assembly S is likewise connected to circuit C so that the recording sheet on drum D lies in a discharge gap between the drum surface and the stylus point. The circuit C includes a capacitor 10, a direct current source or battery 1I series-connected with a resistor 12, and a relay R whose movable contact 13 is normally biased by a spring 14 toward a stationary contact 15 and switches over to another stationary contact 16 when the relay coil 11 is energized to an extent suilicient for overcoming the spring bias. The capacitor is normally connected to the current source 1| and hence in charged condition. When contact 13 switches over to contact16, the capacitor is disconnected from source 1| and discharges itself through the stylus and drum, this discharge being of very short duration so that a dot mark is produced on the recording sheet.

The relay coil 11 derives its energization from a measuring circuit under control by the potentiometer P. A measuring gauge, impulse or signal transmitter is connected across the potentiometer resistor 88, for instance, through an amplier A. The voltage drop along resistor E8, between its terminal points 18 and 19, varies in accordance with the variations of the quantity measured by the gauge and is so rated, relative to the minimum (threshold) excitation required bycoil 11 for actuating the relay contact 13, that the threshold voltage of the relay lies within the range of the expected potentiometric voltage variations. When the slider 66 begins its travel at terminal point 18, the voltage drop across relay coil 11 is zero so that the stylus, now also at the starting point of a rotation, is deenergized. As l the slider 88 travels along resistor 88 toward terminal point 19, it will reach a point where the voltage imposed on the relay coil passes through the threshold value. At this moment, the movable relay contact 13 is switched over so that a self-terminating short-lasting-discharge is released and a recording point produced by the stylus.v While the slider 66 continues its travel, contact 19 remains in engagement with contact 18 so that no further recording action occurs.

At the end point 19 of the slider travel, the coil circuit of the relay is interrupted. While the slider 88 passes from point 19 to point 18, contact 13 returns to contact 15 thus charging capacitor 10 for the next operation.

The point along resistor 88 at which the threshold voltage of the relay is obtained depends on the voltage value imposed on the resistor at that moment andhence is indicative of the quantity to be measured. Since the angular position of the stylus relative to the drum is in a definite relation to that of the slider 66 relative to re sistor 88, the position of the recording mark produced by the stylus on the recording sheet is also indicative of the measured quantity. The recording procedure is repeated during each rotary cycle of stylus motion. Hence, a resultant curve 80 (Fig. l) is recorded representing the variation of the measured quantity versus time.

It will be understood from the foregoing that the recorder drum is non-rotating during the recording operation. As a result the record, represented by curve 80, remains stationary and can be readily observed at all times even at high operating speeds, for instance 600 R. P. M. of stylus rotation. However, the drum can be adjusted to any desired angular position relative to the base structure of the recorder merely by turning the knob 28. This may be used for selecting the lo* cation of the recording sheet on which the diagram is to appear. The rotary adjustability ci the drum is also of advantage in cases where the recorder is mounted so that only one side of the drum is conveniently visible to an observer. That is, by turning knob 20 any part of the diagram can be moved into a desired angular position. This can be done during a recording procedure without causing discontinuity of the record because the drum rotation superimposes on the relative travel between slider 88 and resistor 88 an additive or subtractive component depending upon the direction of drum rotation. Consequently, the relative motion between control members 66 and B8 is always in a given relation to the relative rotation between record producing members S and D,

The foregoing description refers especially to recorders in which one coordinate is time and therefore the axial translation of the stylus assembly derived from the drive lor transmission mechanism for rotating the stylus. For a recorder in which the axial movement represents a magnitude not proportional to time (X-Y-recorder) the gears 58 and 59' are not connected to gear 51 but are geared to a separate drive which is controlled in dependence upon the component magnitude represented by the axial coordinate of the recording. That is, the rotary drive of the stylus and the relative axial translating motion between `stylus and drum can be derived from any two suitable sources of motion under control by different and not necessarily interdependent quantities. For many purposes it is desirable to have the stylus not rotate continuously and to keep the recorder at rest for a period of time after each rotation of the stylus. This can be obtained in either above-described embodiment by employing a start-stop drive instead oi' the continuously running and directly coupled motor 55 (see Fig. 1).

Another recording apparatus including a startstop drive and suitable for facsimile transmission is represented in Fig. 5 by a diagrammatic showing. When in operation, the stylus S and its car rier member M rotate about the drum D and move also axially along the drum, i. e. perpendicularly to the plane of illustration, the' axial translating' means being similar to those of Figs. 1 to 3 and not illustrated in Fig. 5. The gear portion |39 of the stylus carrier M meshes with a gear |50 which is driven by a gear |58 whose shaft |54, in turn, is connected to a drive motor |55 by suitable transmission means represented by the dot-andn dash line |80. The transmission ratio between stylus rotation and revolution of shaft |54 is lzl. The shaft 54 is provided with a stop cam |8| and a control cam |82. The stop cam cooperates with a latch |83 which is pivoted at |84 to a. base plate N and biased by a spring |85 toward engagement with the stop of cam 8|. Plate N carries a release magnet;l |86 which, when energized, turns the latch |83 against its spring bias thereby releasing stop cam |8| and shaft |54 for rotation. Recorder drum D and plate N of the releasablc start-stop mechanism are connected by a ma chanical transmission, here represented by the dot-and-dash line H5, which causes the plate N to follow any rotary displacement of drum D in a 1:1 ratio. In other words, when drum D is turned, by the attendant in order to place the nascent record into a position convenient for observation, the point of engagement between stop cam and latch |83 is shifted around shaft |54in' the necessary proportion to maintain the original angular relation to the recording sheet.

Control cam |82 engages a movable contact |81 connected with another switch contact |88. When the stylus S is at rest, before beginning one of its cycles of rotation, and in an angular position determined by that of the base plate N, cam |83 holds contacts |81 and |88 against stationary contacts |89 and |90 respectively. The release magnet |86 is then connected with the output terminals of a receiver RC. When this receiver obtains a Starting signal, it passes a correspending ampliied impulse to the magnet so that the latch |83 is turned and the stop cam l8l released. As a result, the shaft its, under 'driving torque derived from motor |55, starts revolving so that 'the stylus begins a cycle of motion about the drum. Immediately thereafter cam E82 releases the switch contacts lSland l83. This disconnects the magnet 48B from receiver RC and instead connects the stylus S through a Stationary contact ISI with the receiver terminal oi switch contact l81. pulses are passed from the receiver to the stylus and thence through thefrecording sheet and the drum D to ground for producing one line of the facsimile record. itt the end ci one complete rotation, the stop of cam itl abuts against the latch it so that the stylus is stopped. At the same time, cam it depresses contacts ltl and 88 and prepares the circuit of magnet E86 for the neXt cycle i operation. Due to the connectionv between drum-D and plate-N, the recording operation need not' be interrupted and is not otherwise impaired when the drum is turned by the attendant.

As exemplied by the different embodiments described in the foregoing, and as will be apparent to those skilled in the art especially from a comparison of these embodiments with the operating circuits and structures disclosed in the above-mentioned copending applications, ap- Daratils according to our invention may be modified in various respects without departing from its gist and' essential features as set forth in ,the claims following hereinafter. I

-What we claim es our invention is:

l. A recording apparatus comprising a member ior accommodating a recording sheet, a stylus member disposed ior producing a record on said sheet and being movable relative thereto in two coordinate directions, drive means for producing relative motion between said members in said two directions, adjusting means connected with said sheet-accommodating member for displacing said sheet in parallel to one of said directions, balance-responsiverelay means connected to said stylus member for controlling its marking operation, electric clrcuit means connected to said relay means for controlling said relay means in dependence upon a variable electric quantity, said circuit means including a device disposed for balancing the effect of said quantity on said relay means and having two parts movable relative to each other for varying the balancing effect of said -device over a, given range so as to cause said relay means to respond at an instant when the'relative position of said parts is indicative of said quantity, transmission means connecting one of said parts with said adjusting means so as to move said part in a, given relation to the displacement of said sheet, and transmission means connecting said other-Apart with said drive means so as 1 to move said latter part in a given relation to the relative motion between said members in said one direction.

2. Av recording apparatus comprising a rotary member for accommodating a recording sheet, a stylus vmember for producing a record on said sheet, drive means for moving said members relative to each other in two coordinate directions when said rotary member is non-rotating, one of said coordinate directions being substantially in parallel to the direction of rotation of said rotary member, relay means connected to said stylus member for controlling its marking opera- Hence, the subsequent signal imdii tion, electric circuit means connected to said relay means forcontrolling said relay meals in dependence upon a variable electric cuantity, said circuit means including a potentiometric impedance device having ltwo parts movable relative to each other for varying an impedance value of said device over a given range so as to cause said relay means to respond. at an instant when the relative position `oi said parts is indicative of saidv quantity, transmission means connecting one of said parts with said rotary member so as 'to move said part in a given ratio to rotary displacements of said latter member', and transmission means connecting said other part 'with said' drive means so as to move said latter part in agiven ratio to the relative motion between said stylus member and sheet in' said one coordinate direction.

3. A recording apparatus comprising a rotatable drurn for accommodating a recording sheet, stylus means disposed for producing a record on said sheet and being rotatable about said drum, said drum and stylus means being axially displaceable relative to each other so that said stylus means is operable when said drum is non-rotating, aY start-stop drive-mechanism disposed for intermittently rotating said stylus means and having two releasable latch members rotatable relative to each other for determining the starting points of the individual rotations of said stylus means, and mechanical transmission means connecting said mechanism with said drum and stylus means so as to move said members relative to each other in. accordance with the relative rotary motion between said drum and stylus means.

t. A recording apparatus comprising a rotatable drumior accommodating a recording sheet, stylus means disposed for producing record on said sheet and being rotatable about said drum,

said drum and stylus means being axially displaceable relative to each other so that said stylus means is operablie when said drum is non-rotating, an electrical impedance device disposed for controlling the marking operation of said stylus means and having two members rotatable relative to each other for adjusting its controlling irnpedance eiiect, drive means `for rotating said stylus means and one of said members in a given speed relation to each other, and connecting means between said drum and said other member so that the latter rotates in a given speed relation to said drum when said drum is rotated.v

5. A recording apparatus comprising a rotatiable drum for accommodating a recording sheet,

stylus means disposed for producing a record on said sheet and being rotatable about said drum, said drum and stylus means being axially displaceable relative to each other so that said stylus means is operable when said drum is nonrotating, a potentiometric device disposed for controlling the recording operation of said stylus means in accordance with a quantity to be recorded and having two members movable relative to each other for adjusting its potentiometric control el'ect, drive means for rotating said stylus means and moving one of said members synchronously in a. given relation to each other, and connecting means between said drum and said other member for moving the latter in a given relation to said drum when said drum is rotated.

6. A recording apparatus comprising a rotatable drum for accommodating a recording sheet, stylus means disposed for producing a record on sadisheet and being rotatable about said drum, sai'l drum and stylus means being axially displaceable relative to each other so that said stylus means is operable when said drum is non-rotating, a potentiometric measuring device disposed for controlling the recording operationlof vsaid stylus means in accordance with a quantity to be recorded and having two members movable relative to each other for varying its potentiometric control effect, drive means for rotating said stylus means and moving one of said potentiometer members in a given relation to each other, and connecting means between said drum and said other potentiometer member for moving the latter in a given relation to said drum when said drum is rotated.

7. A recording apparatus comprising a rotatable drum for accommodating a recording sheet, stylus means disposed for producing a record on said sheet and being rotatable about said drum, said drum and stylus means being axially displaceable relative to each other so that said stylus means is operable when said drum is non-rotating, a resistance potentiometer disposed for controlling the recording operation of said stylus means in accordance with a measuring quantity to be recorded and having a resistor and a slide contact rotatable relative to each other, means for rotating said stylus means and slide contact synchronously in a given relation to each other,

and means connecting said drum with said resistor for rotating the latter in a given angular relation to said drum when said drum is rotated.

8. A facsimile recorder comprising a rotatable drum for accommodating a recording sheet, stylus means disposed for producing, when electrically energized, recording marks onsaid sheet and being rotatable about the axis of said drum and axially displaceable relative to said drum so as to be operable when said drum is non-rotating, a start-stop drive mechanism disposed for rotating and relatively displacing said stylus means and `latch members rotatable relative to each other for determining the starting points of the individual cycles of motion of said stylus means, mechanical transmission means connecting said mechanism with said drum and stylus means so as to move said members relative to each other in accordance with the relative rotary motion between said drum and stylus means, and circuit means connected with said stylus means for transmitting energizing impulses thereto.

9. vA recording apparatus comprising a member for accommodating a recording sheet, a stylus member for marking said sheet, said members being movable in two coordinate directions relative to each other, drive means for producing relative motion between said members in said two directions, manually controllable adjusting means connected with said sheet-accommodating member for additionally displacing said sheet relative to said stylus member in parallel to one of said directions, relay means for controlling the marking operation of said stylus member, electric cirmeans for producing relative motion between said cuit means disposed for controlling said relay means in dependence upon a variable electric quantity and including a potentiometric impedance device having two parts movable relative to each other for causing a mark to be produced at an instant when the potentiometric condition of said device is indicative of said quantity, and mechanical transmission means connecting said members with said device for moving said parts relative to each other in a given ratio to the resultant relative motion between said members.

members in said two directions, relay means for controlling the recording operation of said stylus member, an electric device having two parts movable relative to each other for controlling said relay, and adjusting means mechanically connected with said sheet accommodating member and with one of said parts for displacing the sheet relative to said stylus member in parallel to one of said directions while simultaneously displacing said one part relative to said other part, so that the motion of said parts relative to each other maintains a given ratio to the relative motion between said members in said one coordinated direction during displacing motions of the sheet caused by the actuation of said adjusting means.

11. A recording apparatus comprising a rotatable drum member for accommodating a recording sheet, a stylus member rotatable about said drum member, said members being axially displaceable relative to each other so that said stylus member is capable of marking the sheet when said drum is non-rotating, a potentiometric measuring device disposed for electrically controlling the marking operation of said stylus member in accordance with a `quantity to be recorded and having two parts movable relative to each other for controlling the potentiometric condition of said device, and adjusting means mechanically connected with said drum member and said device for rotating said drum member and simultaneously changing the position of said parts relative to each other so that the relative motion between said parts maintains a given ratio to l the resultant relative rotation between said members during the periods of actuation of said adjusting means.

12. A recording apparatus comprising a normally stationary drum for accommodating a recording sheet, stylus means disposed for producing a record on said sheet and being rotatable and axially displaceable relative to said drum so as to be operable when said drum is non-rotating, drive means for axially displacing said stylus means relative to said drum, electric means having a relay for transmitting control impulses to said stylus means so as to cause it to produce recording marks on said sheet indicative of a phenomenon to be recorded, a variable impedance device forming part of said electric means and GEORGE KEINA'I'H. REINHARD K. HELLMANN. 

